The present invention relates to a transmission apparatus for connecting a high-speed data network to a subscriber line in response to a demand from a subscriber. More particularly, the present invention relates to an asymmetric data transmission apparatus using asymmetric digital subscriber lines and relates to a subscriber line connection method employed by the apparatus.
An asymmetric digital subscriber line (xe2x80x9cADSLxe2x80x9d) can achieve high-speed downstream transmission and low-speed upstream transmission by using a frequency band which is higher than the frequency band of a voice signal and by using an existing telephone subscriber line. The downstream transmission represents a transmission from a network to a subscriber, and the upstream transmission represents a transmission from the subscriber to the network.
An asymmetric data transmission apparatus using the ADSL connects a high-speed data network to a telephone subscriber line in response to a demand from a subscriber. Thus, communication services such as video on demand (xe2x80x9cVODxe2x80x9d) and other internet services can he provided via the subscriber line to the subscriber.
The asymmetric data transmission apparatus contains an asymmetric data transmission remote unit (xe2x80x9cremote unitxe2x80x9d) connected to each of the subscriber lines and contains an asymmetric data transmission central unit (xe2x80x9ccentral unitxe2x80x9d) connected between the high-speed data network and the subscriber lines. The central unit communicates with the remote units by using a higher frequency band than the frequency band of the voice signal and comprises subscriber modems. The subscriber modems modulate and demodulate signals transmitted between the high-speed data network and the remote units, and one subscriber modem is fixedly assigned to each subscriber line.
Also, each subscriber modem includes a voice signal splitter, and the voice signal splitter extracts a voice signal and an analog signal from its corresponding subscriber line. The voice signal is used during telephone calls, and the analog signal is a data signal which communicates with the high-speed data network. The voice signal splitter transmits the voice signal to a telephone exchange and prevents the analog signal from being transmitted to the telephone exchange.
The asymmetric data transmission apparatus described above has several disadvantages. For example, since one subscriber modem is fixedly assigned to each of the remote units, a large number of subscriber modems are required and must be in a standby state during the operation of the asymmetric data transmission apparatus. As a result, the resources of the signal lines are wasted, and the cost of the apparatus per signal line increases.
An object of the present invention is to provide an asymmetric data transmission apparatus and a subscriber line connection method employed by the apparatus which can reduce the waste of the line resources and raise the efficiency of the apparatus.
In order to overcome the above and other objects, an asymmetric data transmission apparatus using asymmetric digital subscriber lines, which connects a high-speed data network to telephone subscriber lines in response to a demand of a subscriber, is provided. The apparatus comprises: a plurality of subscriber line connectors which are respectively connected to said telephone subscriber lines, which respectively comprise activation sensors that receive activation signals from remote units via said telephone subscriber lines, and which respectively receive output signals from said remote units and output corresponding received analog signals, wherein said activation signals are requests from said remote units to be respectively connected to said high-speed data network, and wherein a particular subscriber line connector inputs a particular output signal from a particular remote unit via a particular telephone subscriber line and outputs a particular received analog signal; a plurality of subscriber modems which are respectively connected to digital lines of said high-speed data network, which respectively modulate output digital signals transmitted from said high-speed data network via said digital lines into output analog signals, and which respectively demodulate input analog signals into input digital signals and supply said input digital signals to said high speed network, wherein a particular subscriber modem inputs a particular input analog signal and outputs a particular input digital signal; and a connection circuit which selectively connects said particular subscriber modem to said particular subscriber line connector and which inputs said particular received analog signal and outputs said particular input analog signal.
In order to additionally overcome the above and other objects, a method employed by an asymmetric data transmission apparatus using asymmetric digital subscriber lines, which connects a high-speed data network to telephone subscriber lines in response to a demand from a subscriber, said method comprising the steps of: (a) sensing an activation signal via a particular telephone subscriber line from a particular remote unit requesting said particular remote unit to be connected to said high-speed data network, wherein said particular remote unit is one of a plurality of remote units and said particular telephone subscriber line is one of a plurality of telephone subscriber lines respectively connected to said remote units; (b) activating a particular subscriber modem connected to said high-speed data network in response to said activation signal being sensed, wherein said particular subscriber modem is one of a plurality of subscriber modems; and (c) selectively connecting said particular subscriber modem to said particular telephone subscriber line in response to said activation signal being sensed to start a communication.